Laser Beam Welding Application

Laser Beam Welding Process description
Heat for fusion is generated by the absorption of a high power density narrow beam of light, commonly known as a laser. Focusing of the laser is performed by mirrors or lenses.

Materials for Laser Beam Welding

• Dependent on thermal diffusivity and to a lesser extent the optical characteristics of material, rather than chemical composition, electrical conductivity or hardness.
• Stainless steel and carbon steels typically.
• Aluminum alloys and alloy steels difficult to weld. Not used for cast iron.

Laser Beam Welding Process variations

• Many types of laser are available, used for different applications. Common laser types available are: CO2, Nd:YAG, Nd:g lass, ruby and excimer. Depending on economics of process, pulsed andcontinuous wave modes are used.
• Shielding gas such as argon sometimes employed to reduce oxidation.
• Laser beam machines can also be used for cutting, surface hardening, machining (LBM) drilling, blanking, engraving and trimming, by varying the power density.
• Laser beam spot and seam welding can also be performed on same equipment.
• Laser soldering: provides very precise heat source for precision work.

Typical applications of Laser Beam Welding
. Structural sections
. Transmission casings
. Hermetic sealing (pressure vessels, pumps)
. Transformer lamination stacks
. Instrumentation devices
. Electronics fabrication
. Medical implants

Laser Beam Welding Design aspects

• Laser can be directed, shaped and focused by reflective optics permitting high spatial freedom in 2-dimensions. Horizontal welding position is the most suitable.
• Typical joint designs using LBW: lap, butt and fillet (see Appendix B – Weld Joint Configurations).
• Mostly for horizontal welding.
• Balance the welds around the fabrication’s neutral axis.
• Path to joint area from the laser must be a straight line. Laser beam and joint must be aligned precisely.
• Intimate contact of joint faces required.
• Filler rod rarely utilized, but for thick sheets or requiring multi-pass welds, a wire-feed filler attachment can be used.
• Minimal work holding fixtures required.
• Minimum thickness¼0.1 mm.
• Maximum thickness¼20 mm.
• Multiple weld runs required on sheet thickness13 mm.
• Dissimilar thicknesses difficult.

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